Having now retrieved a little more of leasure, both for Delineation and Description, for a further elucidation of what I have said, I shall make it m… - Robert Hooke

At these meetings, which were about the year 1655, divers experiments were suggested, discoursed, and tried with various successes, though no other account was taken of them but what particular persons perhaps did for the help of their own memories; so that many excellent things have been lost. Some few only by the kindness of the authors have since been made public. Among these may be reckoned the Honourable Mr Boyle's Pneumatic Engine and Experiments, first printed in the year 1660; for in 1658 or 1659 I continued and perfected the air-pump for Mr Boyle, having first seen a contrivance for that purpose made for the same honourable person by Mr Gratorix, which was too gross to perform any great matter.

The Publisher of Transactions in that of October 1675 indeavours to cover former injuries done me by accumulating new ones, and this with so much passion as with integrity to lay by discretion; otherwise he would not have affirmed, that it was as certain that none of my Watches succeeded, as it was that I had made them several years ago: For how could he be sure of a Negative? Whom I have not acquainted with my Inventions, since l looked on him as one that made a trade of Intelligence.
Next whereas he says l made them without publishing them to the world in Print, he prevaricates, and would have it believed that they were not published to the world, though they were publickly read of in Sir John Cutlers Lectures before great numbers at several times, and though they were made and shewn to thousands both English and Foreiners, and writ of to several persons absent, and though they were in the year 1665 in the History of the Royal Society published to the world in Print, because, forsooth, they were not printed in his Transactions.
Thirdly, whereas the Publisher of Transactions makes along story of my seeing his Journal De Scavans, and my desiring to transcribe that part of it which concerned this matter, as if l had requested some singular favour thereby, l answer,
First, that he knew I designed presently to have printed it with Animadversions, but he endeavoured to prevent me, designing first clancularly to get a Patent of it for himself, and thereby to defraud me.
Next, I say, I had a right without his favour to have seen, perused, and copied it, as I was one of the Royal Society, the intelligence he there brings in being the Societies. ...
To his upbraiding me with his having published some things of Mine; I answer, he hath so, but not so much with mine as with his own desire, and if he send me what I think worth publishing, l will do as much for him, and repay him in his own coyn.
Lastly, Whereas he makes use of We and Us ambiguously, it is desired he would explain whether he means the Royal Society, or the Pluralities of himself. If the former, it is not so, as l can prove by many Witnesses; if the later, I neither know what he is acquainted with, or what has been imparted or explained to him.
So not designing to trouble my self any further with him, unless he gives me occasion, I dismiss him with his
— Speque metuque
Procul hinc procul ito.

I should here have described some Clocks and Time-keepers of great use, nay absolute necessity in these and many other Astronomical observations, but that I reserve them for some attempts that are hereafter to follow, about the various wayes I have tryed, not without good success of improving Clocks and Watches and adapting them for various uses, as for accurating Astronomy, completing the Tables of the fixt stars to Seconds, discovery of Longitude, regulating Navigation and Geography, detecting the properties and effects of motions for promoting secret and swift conveyance and correspondence, and many other considerable scrutinies of nature: And shall only for the present hint that I have in some of my foregoing observations discovered some new Motions even in the Earth it self, which perhaps were not dreamt of before, which I shall hereafter more at large describe, when further tryalls have more fully confirmed and compleated these beginnings. At which time also I shall explaine a Systeme of the World, differing in many particulars from any yet known, answering in all things to the common Rules of Mechanicall Motions: This depends upon three Suppositions. First, that all Cœlestial Bodies whatsoever, have an attraction or gravitating power towards their own Centers, whereby they attract not only their own parts, and keep them, from flying from them, as we may observe the Earth to do, but that they do also attract all the other Cœlestial Bodies that are within the sphere of their activity; and consequently that not only the Sun and the Moon have an influence upon the body and motion of the Earth, and the Earth upon them, but that Mercury also, Venus, Mars, Saturne, and Jupiter by their attractive powers, have a considerable influence upon its motion as in the same manner the corresponding attractive power of the Earth hath a considerable influence upon every one of their motions also. The second supposition is this, That all bodys whatsoever that are put into direct and simple motion, will so continue to move forward in a streight line, till they are by some other effectual powers deflected and bent into a Motion describing a Circle, Ellipsis, or some other more compounded Curve Line. The third supposition is, That these attractive powers are so much the more powerful in operating, by how much nearer the body wrought upon is to their own Centers. Now what these several degrees are I have not yet experimentally verified;—But these degrees and proportions of the power of attraction in the celestiall bodys and motions, were communicated to Mr. Newton by R. Hooke in the yeare 1678, by letters, as will plainely appear both by the coppys of the said letters, and the letters of Mr. Newton in answer to them, which are both in the custody of the said R. H., both which also were read before the Royall Society at their publique meeting, as appears by the Journall book of the said Society.—but it is a notion which if fully prosecuted as it ought to be, will mightily assist the astronomer to reduce all the Cœlestiall motions to a certaine rule, which I doubt will never be done true without it. He that understands the natures of the Circular Pendulum and Circular Motion, will easily understand the whole ground of this Principle, and will know where to find direction in nature for the true stating thereof. This I only hint at present to such as have ability and opportunity of prosecuting this Inquiry, and are not wanting of Industry for observing and calculating, wishing heartily such may be found, having my self many other things in hand which I would first compleat, and therefore cannot so well attend it. But this I durst promise the Undertaker, that he will find all the great Motions of the World to be influenced by this Principle, and that the true understanding thereof will be the true perfection of Astronomy.